Preparation of ortho-alkylated phenols

ABSTRACT

There are provided alkylation catalysts comprising magnesium oxide mixed with and bonded by manganese oxides. These are used in processes for the vapor phase ortho-alkylation of phenols with an alcohol. The present catalysts are advantageous in that they provide a substantially increased total useful life, a reduced induction period for maximum reaction selectivity, elimination of catalyst losses in comparison with the powders or weakly sintered composites of the prior art and increased selectivity for ortho-substitution. Treatment of the new catalysts with methanol vapor before use enhances their activity in converting phenols to 2,6-xylenol and results in a significant increase in production rate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of copending U.S. patentapplication Ser. No. 846,973, filed Aug. 1, 1969, which in turn is acontinuation-in-part of Ser. No. 717,919, filed April 1, 1968 both nowabandoned.

This invention relates to the ortho-alkylation of phenols and moreparticularly, to the vapor phase ortho-alkylation of phenols by reactionof a non-ortho-alkylated phenol with an alcohol in the presence of acatalyst comprising magnesium oxide mixed with a manganese oxide.

BACKGROUND OF THE INVENTION

In commonly assigned Hamilton U.S. patent application Ser. No. 371,189,filed May 29, 1964, now U.S. Pat. No. 3,446,856, there is disclosed andclaimed a method for methylating the ortho positions of phenol by thevapor phase reaction of a phenol with methanol in the presence ofmagnesium oxide as a catalyst at a catalyst bed temperature in the rangeof 475° to 600°C. Under the conditions described in the Hamilton patent,phenol is selectively ortho-methylated in yields of 95%. Thus, thereaction offers a means for economically converting phenol toortho-cresol, a useful disinfectant and wood preservative and forconverting both phenol and ortho-cresol to 2,6-xylenol, a monomer whichcan be polymerized to form poly(2,6-dimethyl-1,4-phenylene)oxide, a highperformance thermoplastic material.

While the Hamilton patent provides an economic synthesis for both2,6-xylenol and ortho-cresol from phenol, the service life of themagnesium oxide catalyst is relatively short due to the high temperatureat which the reaction is required to take place, i.e., about 90 to 100hours service life at the typical reaction temperature of about 530°C.Also, the magnesium oxide catalyst of the Hamilton patent is onlymoderately selective with respect to methanol, with methanol selectivitybeing in the range of about 40 to 50%. This means more than about twomoles of methanol are required for each mole of methanol entering intothe reaction with phenol. In addition, the use of unmodified magnesiumoxide in powdered form or in the form of a weakly sintered compositeresults in a rather large induction period for maximum selectivity. Theterm "induction period" may be defined as the period from the time ofstarting the reaction to the time at which the catalyst reaches andmaintains maximum ortho-alkylation selectivity. Finally, the use ofmagnesium oxide in powdered or sintered form provides various processingdifficulties.

Many of the above-noted difficulties are overcome by the process of thesaid copending U.S. patent application Ser. No. 717,919, filed Apr. 1,1968. Therein, a process is disclosed for the ortho-alkylation of phenolcomprising the reaction of a phenol having at least one unsubstitutedortho position with an alcohol in the presence of a catalyst consistingof a mixture of magnesium oxide and manganese sulfate.

The catalyst of copending patent application Ser. No. 717,919 isprepared by pulverizing the magnesium oxide and wet-mixing the magnesiumoxide with manganese sulfate and water or, alternatively, byimpregnating the pulverized magnesium oxide with an aqueous solution ofmanganese sulfate. Preferably, the manganese sulfate constitutes from 2to 10% of the catalyst on a dry solids basis. After mixing, it ispreferred to mold the catalyst to a desired shape. It is disclosed thatinteraction between the manganese salt and the magnesium oxide uponcontact with water from wet mixing or impregnation with aqueous solutionis accompanied by the evolution of heat. Since the surface to weightratio of the magnesium oxide is very high, for example, of the order of180 square meters per gram, the heat brings about a noticeable increasein the mixture temperature under normal impregnating or mixingconditions. This appears to result in the formation of a lattice ofenhanced catalytic activity containing the magnesium oxide and manganesesulfate.

With the catalyst of application Ser. No. 717,919, selectivity favoringortho-methylation over meta- or para-methylation is the same as that ofthe Hamilton patent at temperatures as low as 440°C. It is advantageousto operate at temperatures as low as 440°C. instead of, for example,530°C., because catalyst life is extended considerably beforeregeneration or other treatment is needed. Such catalysts have beenoperated without reduction in catalytic activity for periods in excessof 800 hours, in contrast to a maximum life of 90-100 hours for theHamilton catalysts. In addition, the magnesium oxide-manganese sulfatecatalyst is superior because of the increased strength imparted to thecatalyst particles by the manganese oxide lattice formed by the reactionbetween manganese sulfate and magnesium oxide in the presence of water.Therefore, there is much less tendency for particles of catalyst toflake off in operation or from handling and the service life is thusextended with a minimum loss of catalyst.

Although the catalyst of the said copending application Ser. No. 717,919provides the advantages noted above, there is observed an undesirableincrease in the induction period required for maximum reactionselectivity. This means that about 24-100 hours is required to reach amolar phenol selectivity level of over 90%. During the induction period,a relatively large amount of undesired 2,4,6-mesitol is produced. It isbelieved that the presence of the sulfate ion in the catalyst isresponsible for the longer induction period.

It has now been found that magnesium oxide mixed or bonded withmanganese oxide or a mixture of manganese oxides has the advantages ofthe catalyst of the above-noted copending application and also, becausesulfate is eliminated, has the further advantage of having a reducedinduction period for maximum ortho-alkylation selectivity. Thus, thepresent invention contemplates an ortho-alkylation catalyst consistingof magnesium oxide mixed with manganese oxides, substantially free ofsulfate, permitting the ortho-alkylation reaction to proceed with a highdegree of both methanol and phenol selectivity and with a reducedinduction period for maximum selectivity. Moreover, the new catalystsmay be molded to any desired shape and will have strength propertiessufficient to prevent particles of the the catalyst from breaking orflaking off in operation or handling, thus substantially extending theservice life of the catalyst with a minimum of loss during operation. Inaddition the optimum reaction temperature may be reduced from500°-540°C. for conventional catalysts down to 465°-485°C., therebyimproving the overall economy of the process and increasing the catalystlife further.

It has also been discovered that if the catalysts according to thisinvention are treated with methanol vapor before use, there is anunexpected, significant increase in conversion of phenols toortho-alkylated products. This in-situ activation provides an economicalmeans of heating up a large commercial size reactor and results in asignificant increase in production rate, of at least about 50% and more.

Accordingly, a primary object of the present invention is to provide animproved catalyst for the ortho-alkylation of a phenol with an alcoholin a highly selective manner and in high yield.

Another object of the invention is to provide a magnesium oxide catalysthaving superior physical strength properties, which may be molded to anydesired shape and which will have a service life of many hundreds ofhours before needing regeneration or other treatment.

Still another object of the invention is to provide a process forformation of ortho-alklated phenols where the induction period requiredto reach maximum selectivity is low.

A further object of the invention is to provide an activated catalyst byexposure to methanol vapors.

DESCRIPTION OF THE INVENTION

These and other objects are secured according to this invention inproviding a catalyst by mixing magnesium oxide wth manganese oxides,preferably in the form of finely divided powders. Preferably, thepowders of the magnesium oxide and the manganese oxide are maintainedbelow an average particle size of 500 microns in diameter. Thepercentage of manganese oxides in the blend is preferably maintained lowand may be as low as 1% by weight on a dry solids basis or as high as15% or more. The especially preferred range, however, varies from 2 to10% by weight. After the powders are blended, water is added to themixture in an amount sufficient to completely wet it so that the moistmixture may be molded to shape. Typically, one part by weight water isadded for each part of the powder blend. The blend is then molded toshape under pressure, dried at about 200°F. and subsequently calcined atan elevated temperature. A calcination temperature of between 300° and700°F. for a time up to about 3 hours is sufficient, but temperatures ashigh as 850°F. may be used. As water is evaporated from the catalyst,minute pores form and thereby expose the magnesium oxide increasing thecatalyst activity. A surface area of at least 20, and preferably 120 to200 square meters per gram of catalyst is desirable. The shape of thecatalyst may be in the form of pellets, Rasching rings, cylinders,tablets or any other shape known to the art.

The magnesium oxide used as a catalyst in conjunction with the manganeseoxides is a material having a very high surface to weight ratio.Magnesium oxide having the desired porosity may be prepared by thermallydecomposing magnesium carbonate, basic magnesium carbonate or magnesiumhydroxide as these materials may be converted to magnesium oxide withoutfusing or sintering.

The manganese oxides may be manganese oxide (MnO), dimanganese trioxide(Mn₂ O₃), trimanganese tetroxide (MN₃ O₄), manganese heptoxide (Mn₂ O₇)as well as other complex oxides of manganese, and mixtures of suchoxides. Especially preferred are dimanganese trioxide and trimanganesetetroxide. Manganese oxide may be obtained by precipitation from anaqueous solution of manganese sulfate by mixing with an alkali such aspotassium hydroxide. However formed, best results are obtained if themanganese oxides powders are washed with distilled or slightly alkalinewater until substantially free of ions, especially sulfate and potassiumions.

In a preferred feature, the catalyst prepared as described above isactivated by exposing it to methanol vapor, e.g., by heating at atemperature of at least about 250°C., until activation is substantiallycomplete. In one manner of proceeding, a catalyst according to thisinvention, e.g., magnesium oxide containing 2 or 5% of Mn₂ O₃ is exposedto condensing methanol vapor for about 23 hours. The methanol can bevaporized in a separate, empty reactor at a temperature of about250-300°C., then fed to the reactor containing the heated catalystsamples. The temperature of the catalyst can be raised to about 465°C.during 5 hours and maintained for another 16 hours. These times areillustrative, not critical -- it is merely necessary to heat thecatalyst with methanol vapor at a temperature above 250°-300°C. unitlactivation of the catalyst is substantially complete.

According to this invention ortho-alkylated phenols are formed by aprocess which comprises vapor-phase reaction of an alkyl alcohol, e.g.,a saturated aliphatic alcohol such as methyl, ethyl, propyl, isopropyl,butyl, isobutyl, tert.-butyl, amyl isoamyl, hexyl, heptyl, octyl, nonyl,decyl, undecyl, lauryl, cetyl, cyclohexyl, and the like, alcohols, andespecially preferably an alcohol containing up to 6 carbon atoms andmost preferably methanol, and a phenol having at least one unsubstitutedortho position in the presence of the catalyst of this invention at atemperature of at least 420°C., and preferably at a temperature varyingbetween 460° and 500°C., and especially preferably at 465°-485°C. Ingeneral, the process conditions are similar to those disclosed in theabove-noted Hamilton patent, but differ therefrom primarily in thesubstitution of the catalyst of this invention and by use of a lowerreaction temperature.

While the invention has been described as applying specifically tophenols and ortho-cresol, it may be applied in general to any phenolhaving an ortho-hydrogen. For example, it also may be used withortho-phenyl phenol, ortho-ethyl phenol, and phenols in which there arealkyl and aryl groups in the meta- and para-positions. These phenols maybe represented by the formula: ##SPC1##

where each R is a monovalent substituent selected from the groupconsisting of hydrogen, alkyl, e.g., C₁ -C₁₂ alkyl, phenyl andalkyl-substituted phenyl, e.g., C₁ -C₁₂ alkyl-substituted phenyl.

In carrying out the alkylation in accordance with this invention, anyone or a mixture of phenols having an ortho-hydrogen may be vaporizedand passed through a reactor heated to a suitable temperature, e.g., atleast 200°C., and preferably at least 420°C., containing the magnesiumoxide-manganese oxides catalyst of the invention. In order to obtain themaximum yield of ortho-alkylated products, at least one mole of thealkyl alcohol and preferably from 1 to 3 moles of the alcohol are usedfor each ortho position on the phenol to be alkylated. For example, ifphenol, which has two-ortho hydrogens per molecule, is to be methylatedto produce a maximum yield of 2,6-xylenol, it is desirable to use two tosix moles of methanol for each mole of phenol with higher yields beingobtained with higher ratios of methanol to phenol.

The vapors issuing from the reactor are condensed and the productseparated by conventional methods such as crystallization, distillation,etc. The reaction proceeds at atmospheric pressure, but it is obviousthat pressures above or below may be used.

As will be apparent to those skilled in the art, the process can becarried out under a variety of reaction conditions. These conditions aretemperature, pressure, flow rate of reactants, vapor space velocity ofthe reactants over the catalyst, contact time of the reactants with thecatalyst, length of the catalyst bed, specific activity of theparticular catalyst, etc. The effects of these reaction variables arethose to be expected from a consideration of the technical aspects ofthe reaction involved. For example, the reaction of alcohol with thephenol compound to produce the desired ortho-alkylated products proceedsfaster as the catalyst bed temperature is increased provided that thetemperature is not so high that secondary reactions such asdecomposition of the reactants or products occur to decrease the yieldof desired product. Such secondary reactions do not occur to anyappreciable extent in this reaction up to a temperature of about 500°C.Above 500°C., decomposition of the reactants and product becomes aproblem because it deposits carbon on the catalyst, decreasing itsactivity. In contrast to prior art catalysts, in the range of from 275°to 500°C. when using a high proportion of methanol to phenol, i.e., 2-3times the amount of methanol required to methylate each ortho-positionof the phenol, the tendency to decompose methanol to gaseous products isdecreased. Below a temperature of 200°C., the reaction of methanol withthe phenol is so slow that the yield of product per hour per volume ofcatalyst is so low as to make the reaction uneconomical to carry out,regardless of the reaction conditions.

In accordance with well known techniques to compensate for lower ratesof reaction, if, for example, less reactive phenolic compounds oralkanols are used, a longer contact time of the reactants with thecatalyst can be used. This may be done by changing any one or several ofthe variables which decrease the vapor space velocity of the reactantsover the catalyst, thus increasing the contact time. Examples of thisare increasing the amounts of catalyst, decreasing the flow rate ofreactants, increasing the pressure in the reactor, etc. At the lowerflow rates, there is some tendency for the selectively to decreasebecause the longer contact time does permit any product which has beencompletely substituted in the two ortho-positions in the initial part ofthe reaction to have time to react further to produce somepara-substituted product. This loss in selectivity can be compensated byincreasing the space velocity but not the flow rate of reactants byusing an inert diluent for the reactants; for example, an inert gas,i.e., nitrogen, argon, etc., or an inert vapor, i.e., benzene, toluene,etc., or by using a lower pressure in the reactor.

If it is desired to use pressure, the flow rate of the reactants can beincreased to give an equal contact time. It, of course, will berecognized that it is possible to have a flow rate of reactants sogreat, either with or without pressure, that the effective contact timeis reduced to an economically unsatisfactory level.

Generally, reaction conditions are chosen so as to minimize the amountof unreacted feed materials which must be recovered and reused. However,reaction conditions which on the face might appear undesirable from anover-all yield point of view may be desirable from an economic point ofview because of the very high degree of selectivity of the reactionunder such conditions to give exclusively only ortho-alkylated products.On the other hand, reaction conditions can also be adjusted to give highover-all yields in terms of pounds of ortho-alkylated product per hourper volume of catalyst when a very small yield of para-substitutedproduct can be tolerated.

It will also be recognized that, because of differences in the specificactivities of the catalysts, each particular catalyst will havedifferent optimum reaction conditions than another catalyst. The morereactive the catalyst, the shorter the contact time needs to be to givethe same degree of conversion to ortho-alkylated products. Therefore, ahigher space velocity or a lower temperature may be used with a morereactive catalyst. It has been found that a catalyst which has not beenused in the reaction, or has been regenerated, has an induction periodduring which time the selectivity of the catalyst increases until itreaches a maximum which it maintains for a long period of time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order that those skilled in the art may better understand theinvention, the following examples are given by way of illustration andnot by way of limitation.

In the examples, the reactor consists of a reservoir containing asolution of alcohol and phenol compound, connected to a metering pumpwhich feeds the reactants through a 1/4 inch stainless steel tube into avertical vaporizer made from a 12-inch long piece of 1 inch O.D. × 0.8inch I.D. stainless steel tubing. The vaporizer is partially immersed ina bath of fused salt to a depth of about 6 inches. The vapors from thevaporizer are fed to an 0.8 inch I.D. stainless steel tube reactorthrough a 1 inch length of 0.25 inch I.D. stainless steel pipe located5.50 inches above the bottom of the vaporizer and connected to thereactor 13 inches from its bottom. The reactor is 24 inches long and isimmersed in the fused salt bath to a depth of 14 inches. Since the inlettube of the reactor coming from the vaporizer also passes through thefused salt bath, it serves as a preheater for the vapor issuing from thevaporizer to bring the vapor up to the temperature of the reactor. Thereactor is equipped with a thermowell made from 1/8 inch stainless steeltubing concentrically located in the reactor and extending downwardsinto the catalyst bed to a depth of 1 to 6 inches. Thus the catalyst bedtemperature can be measured throughout a large section of the tube. Thereactor tube is filled with about 20 ml. of glass beads and then 100 ml.of catalyst is introduced which fills the tube to a depth of 14 inches.The reactant vapors are fed to the top of the catalyst bed and productvapors leave the bottom of the reactor through a 3/8 inch O.D. stainlesssteel outlet tube. The product vapors are led to a water-cooledcondenser and receiver.

EXAMPLE 1

A catalyst is prepared by blending 200 grams of commercial magnesiumoxide with about 6 grams of a mixture of manganese oxides precipitatedfrom an aqueous solution of manganese sulfate mixed with an aqueoussolution of potassium hydroxide and washed with water until sulfate ionfree. The mixture of magnesium oxide and manganese oxide is mixed withabout an equal amount of water and the so-formed blend is molded intocylindrically shaped pellets having a diameter and length of 3/16inches. The catalyst is dried at 200°F. and calcined by heating to about450°F. for about 3 hours. The catalyst is then placed in a reactor whichis maintained at 460°C. The feed composition is vaporized and the vaporsare passed through the catalyst chamber. The conditions and results aresummarized in Table I:

                  TABLE I                                                         ______________________________________                                        Feed Composition      Run 1                                                   ______________________________________                                        Molar Ratio Methanol to Phenol                                                                      6:1                                                     Wt. % Water in Feed   6                                                       Operating Conditions                                                          Temperature (°C.)                                                                            460                                                     LHSV (hr.sup.-.sup.1)*                                                                              2.03                                                    Pressure (psig)       0                                                       Phenolic Distribution (wt.%)                                                   o-cresol             10.1                                                     2,6-xylenol          65.4                                                     2,4,6-mesitol        1.1                                                      Phenol               23.4                                                    ______________________________________                                         *LHSV is the liquid hourly space velocity and defines the volume of liqui     per volume of catalyst per hour.                                         

From the above table, it can be seen that the alkylation takes placeprimarily in the ortho position. The ortho-cresol formed in the reactionand unreacted phenol may be recycled if desired. By increasing theliquid hourly space velocity, the ratio of ortho-cresol to 2,6-xylenolmay be substantially increased. For example, using substantially thesame reaction conditions, an increase in the space velocity to about3.50 hrs⁻ ¹ results in a phenolic distribution comprising about 45%unreacted phenol, 38% ortho-cresol, 16% 2,6-xylenol and less than 1%2,4,6-mesitol.

EXAMPLE 2

The procedure of Example 1 is repeated. In Run 2a, the catalyst used issubstantially the same as that of Example 1. In Run 2b, the catalyst isprepared by pelletizing and calcining substantially pure powderedmagnesium oxide at a temperature of about 500°F. The conditions andresults are as indicated in Table II:

                  TABLE II                                                        ______________________________________                                        Feed Composition      Run 2a   Run 2b                                         ______________________________________                                        Molar ratio Methanol to Phenol                                                                      6:1      6:1                                            Wt. % water in feed   10       12.4                                           Operating Conditions                                                          Temperature (°C.)                                                                            489      504                                            LHSV (hr..sup.-.sup.1)                                                                               1.83     1.65                                          Pressure (psig)        0        0                                             Results                                                                       Induction Period (hrs.)                                                                              8       23.5                                           Molar Phenol Selectivity.sup.(1)                                                                    93.7     89.5                                           Molar Methanol Selectivity.sup.(2)                                                                  72.5     59.5                                           Production Rate       19.3     14.0                                           (lbs. 2,6-xylenol/hr./ft. catalyst)                                           ______________________________________                                         .sup.(1) The molar phenol selectivity is defined as the ratio of phenol       converted to 2,6-xylenol to phenol converted to 2,6-xylenol and               by-products multiplied by 100. The amount of phenol converted to              ortho-cresol is not included in the definition as it is recycled in the       feed stream if desired.                                                       .sup.(2) The molar methanol selectivity is defined as the ratio of            methanol reacted to form 2,6-xylenol to the methanol reacted to form          2,6-xylenol and by-products multiplied by 100. The amount of methanol         converted to ortho-cresol is not included in the definition as it is          recycled in the feed stream if desired.                                  

The life of the catalyst of Run 2a is found to be in excess of 1000hours compared to a life of approximately 75 hours for the conventionalcatalyst of Run 2b. From Table II, it can also be seen that theinduction period for the reaction using a catalyst according to thisinvention is shorter than for the prior art magnesium oxide catalyst.Moreover, methanol selectivity is substantially improved. The CrushingStrength of the catalyst of Run 2a is found to be approximately 56pounds. This compares to a Crushing Strength of approximately 5 poundsfor the conventional catalyst of Run 2b, both tests being run on thesides of cylindrical pellets.

EXAMPLE 3

A catalyst is prepared by dry-mixing magnesium oxide powder with 5 wt.%of di-manganese-trioxide (Mn₂ O₃), followed by wetting, pelletizing anddrying as described in Example 1. After calcining for 3 hours at 600°F.,the crushing strength is 31 lbs. as opposed to about 5 lbs. for aconventional magnesium oxide catalyst.

The catalyst is placed in a reactor which is maintained at 480°C. Thefeed composition is vaporized and the vapors are passed through thecatalyst chamber (Run 3a). For comparison purposes a conventionalmagnesium oxide catalyst is used (Run 3b). The conditions and resultsare summarized in Table III.

                  TABLE III                                                       ______________________________________                                        Feed Composition    Run 3a    Run 3b                                          ______________________________________                                        Molar Ratio Methanol to Phenol                                                                    6:1       5:1                                             Wt. % Water in Feed 6         12.4                                            Operating Conditions                                                          Temperature (°C.)                                                                          480       539                                             LHSV (hr.sup.-.sup.1)                                                                             2.5       0.55                                            Pressure (psig)     0         0                                               Results                                                                       Elapsed Run Time (hrs)                                                                            200       72                                              Product Rate        25        4                                               Phenolics distribution (wt.%)                                                  o-cresol           18.6      46.3                                             2,6-xylenol        50.2      40.0                                             2,4,6-xylenol      2.9       0.7                                              phenol             28.1      13                                              Total duration of Run (hrs)                                                                       400       200                                             ______________________________________                                    

It is seen that the operating temperature with a catalyst according tothis invention (Run 3a) can be maintained at about 480°C. as opposed to539°C. for the conventional, commercially available magnesium oxidecatalyst (Run 3b). It is also found that with the catalyst of Run 3a,the molar phenol selectivity reaches a level of over 90% in less than 8hours, as opposed to about 24-100 hours for the conventional catalyst ofRun 3b. The process using the catalyst according to this invention (Run3a), therefore, is characterized by the surprising absence of anylasting induction period and quickly reaches a high selectivity forortho-alkylation.

EXAMPLE 4

The procedure of Example 3 is repeated substituting for the di-manganesetrioxide, an equal weight of tri-manganese tetroxide (Mn₃ O₄).Substantially the same results are obtained.

EXAMPLE 5

Two catalysts are prepared by the procedure of Example 3 containing,respectively, 5 wt.% (Run 5a) and 2 wt.% (Run 5c) of di-manganesetrioxide, Mn₂ O₃. Approximately 100 ml. each are exposed to methanolwhich has been vaporized in separate, empty reactors, which are locatedin a salt bath at a temperature of about 300°C., then led to thereactors containing the catalyst samples. After 23 hours, these tworeactors, together with a third one which serves as a control andcontains approximately 100 ml. of the 5% Mn₂ O₃ catalyst (Run 5b), areplaced in the salt bath at 300°C. and the methanol flow through themethanol vapor treated catalyst is continued. Nitrogen is passed throughthe control at 2 cubic feet per hour. The temperature in the salt bathis increased to 465°C. during 5 hours, and these conditions aremaintained for an additional 16 hours. For comparison purposes, a 2% Mn₂O₃ control is also used (Run 5d ). The conditions and results aresummarized for three different elapsed times (measured from thebeginning of the runs) in Table IV:

                                      TABLE IV                                    __________________________________________________________________________                          % 2,6-xylenol                                                    Hrs.         in phenolics                                                     into                                                                              Temp.,                                                                            Flow of Reactor                                                                             Production                                     Run                                                                              Catalyst                                                                            Run °C.                                                                        ml./hr.                                                                            effluent rate                                           __________________________________________________________________________    5a 5%    2   463 253  36.8     19.9                                           5b 5% control                                                                          2   463 234  22.6     10.5                                           5c 2%    2   469 270  37.6     21.5                                           5d 2% control                                                                          2   469 220  31.3     14.2                                           5a 5%    73  473 268  60.6     34.6                                           5b 5% control                                                                          73  473 270  31       16.5                                           5c 2%    73  473 268  51.7     29.1                                           5d 2% control                                                                          67  486 250  48.3     25.3                                           5a 5%    172 478 254  64.2     34.7                                           5b 5% control                                                                          172 478 255  35.3     17.9                                           5c 2%    174 478 254  43.8     22.8                                           5d 2% control                                                                          170 483 240  33.9     16.4                                           __________________________________________________________________________

It is noteworthy that the 2% control (Run 5d) had a higher optimumoperating temperature and a still lower production rate than the samecatalyst preactivated with methanol vapor (Run 5c).

The overall results in Table IV demonstrate that there is an unexpected,significant increase in the conversion of phenol to 2,6-xylenolfollowing treatment of the catalyst according to this invention withmethanol vapor.

EXAMPLE 6

A catalyst comprising magnesium oxide and 5% by weight of dimanganesetrioxide (Mn₂ O₃) is prepared by the procedure of Example 3. It isdivided into three portions, one is treated with methanol vapor, one istreated with nitrogen gas and the third is heated in the air at 455°C.(850°F.) for 3 hours. The start-up conditions were as follows:

    Steps nitrogen start-up  methanol start-up                                    ______________________________________                                        (1)   insert in salt bath at 250°C.                                                              same                                                (2)   bleed with N.sub.2 at 2 SCFH for                                              1/2 hr.             same                                                (3)   continue N.sub.2 flow                                                                            start MeOH flow at                                                             250 ml/hr.                                          (4)   raise temp. to 370°C. in 3 hrs.                                                            same                                                (5)   hold temp. at 370°C. for 36 hrs.                                                           same                                                (6)   increase temp. to 465°C. in                                            increments of 20°C./hr.                                                                    same                                                (7)   hold at 465°C. for 16 hours.                                                               same                                                (8)   same               bleed with N.sub.2 for 1/2hr.                        (9)   remove from salt bath                                                                             same                                                ______________________________________                                        SCFH means standard cubic feet per hour                                   

The physical properties are measured and summarized in Table V:

                  TABLE V                                                         ______________________________________                                                                      Catalyst                                                    N.sub.2 MeOH      heated                                                      Start-up                                                                              Start-up  at 455°C.                                ______________________________________                                        Average crush                                                                  strength (pounds)                                                                          4.8       7.9       6.4                                         Total volatiles, %                                                             at 1750°F.                                                                          3.83      8.75      4.22                                        Chemical analysis                                                              Wt.% Carbon  0.34      1.20      0                                            Wt.% manganese,                                                               as Mn.sub.2 O.sub.3                                                                        4.77      5.40      4.80                                        Surface area, m..sup.2 /g.                                                                  106       240       140                                         Pore volume, cc./g.                                                                         0.43      0.45      0.44                                        Pore diameter, A                                                                            163       74        125                                         ______________________________________                                    

All three catalysts are included within the scope of this invention. The"Catalyst with MeOH start-up" is a preferred embodiment because suchcatalysts are more active than the catalyst without (as is shown by thecomparative results in Example 5).

As is seen by the data in Table V, the methanol vapor treated catalystalso has a higher crush strength than the nitrogen-treated or heatsintered embodiments.

Furthermore, although the mechanism by which the changes in physicalproperties have been induced is not clearly understood, a surprisinglylarge increase, of about 70%, in surface area is observed in themethanol treated sample. On the other hand, substitution of nitrogen formethanol causes a decrease of about 24% in surface area.

Although the pore volumes remain about constant, the average porediameter, which is calculated by the formula: ##EQU1## is smaller afterthe methanol treatment and larger after the nitrogen treatment.

EXAMPLE 7

The procedure of Example 1 is repeated, substituting for the methanolstoichiometrical amounts of the following alkanols: ethyl, propyl,n-butyl, isopropyl, isobutyl, tertiary butyl, n-amyl and n-hexyl. Thereare obtained, respectively, phenols, mono- and di-ortho-substituted withethyl, propyl, n-butyl, isopropyl, isobutyl, tertiary butyl, n-amyl andn-hexyl groups.

EXAMPLE 8

The procedure of Example 1 is repeated substituting for the phenol,stoichiometrical amounts of the following phenolic compounds with atleast one ortho-hydrogen:

o-cresol;

m-cresol;

p-cresol;

3,5-xylenol; and

2-phenylphenol

The predominating products are, respectively:

2,6-xylenol;

2,3,6-trimethylphenol;

2,4,6-trimethylphenol;

2,3,4,6-tetramethylphenol; and

2-methyl-6-phenylphenol.

Similarly, after substituting for phenol the following phenoliccompounds:

2,3-xylenol;

2,4-xylenol;

2,5-xylenol;

2,3,4-trimethylphenol;

2,3,5-trimethylphenol;

3,4,5-trimethylphenol;

2,3,4,5-tetramethylphenol;

4-phenylphenol;

2-tolylphenol;

2,4-diphenylphenol;

2,3-diphenylphenol;

2-xylylphenol;

2-mesitylphenol;

2-durylphenol;

4-methyl-2-phenylphenol;

2-tolyl-4-phenylphenol;

2-phenyl-4-tolylphenol; and

3-methyl-5-phenylphenol,

in the procedure of Example 1 there are obtained the correspondingmono-ortho-methylated and di-ortho-methylated phenols, depending onwhether one or two of the ortho-positions is unsubstituted in thestarting material.

Although the above examples have shown various modifications andvariations of the present invention, other modifications and variationsare possible in light of the above teachings. It is therefore to beunderstood that changes may be made in the particular embodiments of theinvention described which are within the full intended scope of theinvention as defined by the appended claims.

I claim:
 1. In a process for alkylating a phenol in the ortho positionwhich comprises the vapor phase reaction in the presence of analkylation catalyst of an alkyl alcohol and a phenol compound having thegeneral formula: ##SPC2##where R is a monovalent substituent from thegroup consisting of hydrogen, alkyl, phenyl and alkyl substitutedphenyl; the improvement comprising conducting the reaction in thepresence of a catalyst comprising magnesium oxide bonded with from 1-15%by weight of manganese oxides.
 2. The process of claim 1 wherein saidalcohol is methyl alcohol.
 3. The process of claim 2 wherein thecatalyst is maintained at a temperature of at least 420°C.
 4. Theprocess of claim 2 wherein each R in said phenol compound is hydrogen.5. The process of claim 2 wherein said phenol compound is ortho-cresol.6. The process of claim 2 wherein said phenol compound is a mixture ofphenol and ortho-cresol.
 7. The process of claim 1 wherein saidmanganese oxides are selected from the group consisting of manganeseoxide, dimanganese trioxide, trimanganese tetroxide, manganese heptoxideand mixtures thereof.
 8. The process of claim 1 wherein the manganeseoxide binder is substantially free of sulfate ions and is formed byprecipitation from an aqueous solution of manganese sulfate by contactwith an alkali.
 9. The process of claim 1 wherein the manganese oxidescomprise from 1 to 15% by weight of the total catalyst.
 10. The processof claim 1 wherein the manganese oxides comprise from 2 to 10% by weightof the total catalyst.
 11. The process of claim 1 including the step ofenhancing the activity of the catalyst by exposing it to methanol vaporbefore conducting the alkylation reaction.
 12. The process of claim 11wherein the catalyst is exposed to methanol vapor at a temperature of atleast about 250°C. until activation of the catalyst is substantiallycomplete.
 13. In a process for alkylating phenol in the ortho positionto form 2,6-xylenol which comprises the vapor phase reaction in thepresence of an alkylation catalyst of an alkyl alcohol and phenol; theimprovement comprising conducting the reaction in the presence of acatalyst comprising magnesium oxide bonded with from 1-15% by weight ofmanganese oxides.
 14. In a process for alkylating a phenol in the orthoposition which comprises the vapor phase reaction in the presence of analkylation catalyst of an alkyl alcohol and a phenol compound having thegeneral formula: ##SPC3##where R is a monovalent substituent from thegroup consisting of hydrogen, alkyl, phenyl and alkyl substitutedphenyl; the improvement comprising conducting the reaction in thepresence of a methanol vapor activated catalyst which comprisesmagnesium oxide bonded with from 1-15% by weight of manganese oxides.15. In a process for alkylating a phenol in the ortho position whichcomprises the vapor phase reaction in the presence of an alkylationcatalyst of an alkyl alcohol and a phenol compound having the generalformula: ##SPC4##wherein R is a monovalent substituent from the groupconsisting of hydrogen, alkyl, phenyl and alkyl substituted phenyl; theimprovement which comprises conducting the reaction in the presence of acatalyst prepared by blending a mixture of magnesium oxide with from1-15% by weight of manganese oxide with about an equal amount of water,molding the blend to shape, and heating at a calcination temperature offrom 300-850°.